public static byte[] SymetricDecrypt(byte[] bytes, string Key)
{
MemoryStream ms = new MemoryStream();
System.Security.Cryptography.SymmetricAlgorithm rijn = SymmetricAlgorithm.Create();
byte[] key = Encoding.ASCII.GetBytes(Key);
byte[] rgbIV = key;
CryptoStream cs = new CryptoStream(ms, rijn.CreateDecryptor(key, rgbIV), CryptoStreamMode.Write);
cs.Write(bytes, 0, bytes.Length);
cs.Close();
return ms.ToArray();
}